The Night King

When The Night King enters the battlefield,
Amass 3
{x}{s} Return target creature with converted mana
cost x or less from a graveyard to the battlefield
tapped under your control. It is a zombie in
addition to its other creature types.
When The Night King dies, sacrifice 3 other
zombies you control. At least one must be
legendary if possible, or two if you control any
permanents that you do not own.